Question Detail

217 * 217 + 183 * 183

  • 70578
  • 82578
  • 80578
  • 80568

Answer: Option C

Explanation:

\begin{aligned}
\frac {1}{2}\times 2(a^2 + b^2) = \frac {1}{2} \times [(a + b)^2 + (a - b)^2]
\end{aligned}
\begin{aligned}
= \frac {1}{2} \times [(217 + 183)^2 + (217 - 183)^2] = 80578
\end{aligned}
Similar Questions :

1. \begin{aligned}
46^2 - (?)^2 = 4398 - 3066
\end{aligned}

  • 23
  • 18
  • 38
  • 28

Answer: Option D

2. 1939392 * 625

  • 1212120010
  • 1212120000
  • 1212120011
  • 1212121010

Answer: Option B

Explanation:

Trick: when multiplying with \begin{aligned} 5^n
\end{aligned} then put n zeros to the right of multiplicand and divide the number with \begin{aligned} 2^n
\end{aligned}
So using this we can solve this question in much less
time.
\begin{aligned} 1939392 \times 5^4 = \frac {19393920000}{16} = 1212120000
\end{aligned}

3. 7589 - X = 3434

  • 4155
  • 2321
  • 3155
  • None of above

Answer: Option A

4. 587 * 999 = ?

  • 586411
  • 586413
  • 486411
  • 486413

Answer: Option B

Explanation:

Trick: 587 * (1000 - 1) = 587000 - 587 = 586413

5. What is the largest 4 digit number exactly divisible by 88

  • 9900
  • 9999
  • 9988
  • 9944

Answer: Option D

Explanation:

Largest 4 digit number is 9999
After doing 9999 ÷ 88 we get remainder 55
Hence largest 4 digit number exactly divisible by 88 = 9999 - 55 = 9944

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